Fork lift attachment with tiltable forks that slides freely on a support bracket



S. P. SMITH FORK LIFT ATTACHMENT WITH TILTABLE FORKS THAT 7 March 30, 1965 SLIDES FREELY ON A SUPPORT BRACKET 3 Sheets-Sheet 1 1 Filed NOV. 5, 1962 INVENTOR.

SAMUEL P SMITH BY Anvs.

March 30, 1965 s. P. SMITH 3,175,721

FORK LIFT ATTACHMENT WITH TILTABLE FORKS THAT SLIDES FREELY ON A SUPPORT BRACKET Filed Nov. 5, 1962 3 Sheets-Sheet 2 u I ID i: /E

I7 I; \l I E A5 INVENTOR.

s. P. SMITH 3,175,721 MENT WITH TILTABLE FORKS THAT March 30, 1965 FORK LIFT ATTACH SLIDES FREELY on A SUPPORT BRACKET 3 Sheets-Sheet 3 Filed NOV. 5, 1962 INVENTOR. SAMUEL P.

SMITH Paws.

United States Patent 3,175,721 FORK LIFT ATTACHMENT WITH TILTABLE FORKS THAT SLIDES FREELY ON A SUP- PQRT BRACKET Samuel P. Smith, Moses Lake, Wash. (2203 E. 10th St., The Dallas, Oreg.) Filed Nov. 5, 1962, Ser. No. 235,447 4 Claims. ((31. 214-700) This invention relates to a novel fork lift attachment designed primarily for use on vehicles such as a truck, trailer, or modified farm vehicle. The device is primarily concerned with moderately light lifting, such as might be encountered in a farm or machinery operation.

It is a first object. of this invention to provide a fork lift attachment which may be readily mounted on an existing vehicle bed without requiring modification of the vehicular structure itself. The attachment is self supporting on a bed and requires only the securing of a fixed bracket to the bed structure.

Another object of this invention is to provide such a device with a low power requirement having a. lifting capacity adequate for farm purposes. The particular device described below is capable of operating with maximum loads of approximately 1000 pounds, such as might be encountered in an orchard when carrying bins of fruit from the trees to a centralized loading point.

Another object of this invention is to provide such a forklift attachment which is extremely simple both in structure and in operation and which may be readily mounted or repaired without requiring specialized mechanical skills.

These and further objects will be evident from a study of the following disclosures taken in conjunction with the accompanying drawings which illustrate one preferred form of the invention. It is to be understood that this form is not intended to limit the scope of the invention as it is defined in the claims which follow this disclosure.

In the drawings:

FIGURE 1 is a fragmentary rear View of a vehicle showing the present attachment mounted thereon;

FIGURE 2 is a top view of the attachment illustrated in FIGURE 1;

FIGURE 3 is a rear View of the attachment shown in FIGURE 1;

FIGURE 4 is an enlarged sectional view taken along line 4-4 in FIGURE 2;

FIGURE 5 is an enlarged perspective view of the attachment as mounted; and

FIGURE 6 is an enlarged sectional view taken along line 66 in FIGURE 2 within the elevated fork position being shown in dashed lines.

The attachment to be described below is particularly designed for use on a farm vehicle such as a light truck or even a modified type of sedan.

As shown in the drawings, the vehicle or truck includes a rear bed It) which is normally fiat and open to the rear of the vehicle. At the rear edge of the bed 10 is mounted a bracket 11 which includes a surface 12 extending downwardly and rearwardly from the bed It). The surface 12 is bounded by rearwardly directed side ledges 13 which provide the lateral boundaries for the fork movement. The surface 12 is maintained by upright standards 14 and a bottom ledge 15 to complete a solid, rigid bracket 11.

Slidably mounted on the surface 12 of bracket 11 is a. fork structure 15, including rearwardly protruding forks 1S, and rigid lateral braces 17. This unitary structure is somewhat conventional in fork lifts and is designed to protrude beneath a pallet or other mounting device positioned below the load to be lifted thereby. It is important to notice from the drawings, particularly FIGURE. 6, that the angle of the forks 13 may be shifted as the forks 13 are lifted. The angular relation of forks 18 is controlled by means of stabilizer rods 19 at each side of the fork structure 16. See FIGURE 2. Each stabilizer rod is a rigid straight member having a threaded connection 20 by means of which the length of the rod 19 may be selectively varied. The individual rods 19 are pivoted to the fork structure 16 at pivot 21 and are anchored to the bed 10 of the vehicle by pivot 22. Thus, as the forks 18 are lifted, the rods 19 will tend to draw back on the upper end of the fork t8 and thereby tilt the. forks 18 as shown in dashed lines in FIGURE 6. In order to prevent. forward tipping of the forks 18, it is necessary that the rod 19 never assume a position below the horizontal.

Lifting of the fork structure 16 is accomplished by means of a cylinder 23 which is preferably a hydraulic cylinder. The cylinder 23 slidably mounts a reciprocable piston rod 24 having a pulley 25 rotatably mounted at the upper end thereof about a horizontal axis. The pulley 25 abuts the central portion of a short cable 26 which is anchored at one end to the bracket 11 and at its remaining end to the brace 17 of the fork structure 16. Thus upward travel of the piston rod 24 will cause the forks 18 to be lifted an equal distance. The cable 26 leaves the fork structure 16 free to maintain whatever angular position is dictated by the stabilizer rods 19 relative to the tapered surface 12 of bracket 11.

The above structure is exceedingly simple, both in structure and in operation. It is to be noted that the only connections between the bed of the truck and the attachment is that connection which exists between the bracket 11, rods 19 and bed It The rods 19 also extend back to the truck bed to provide a stabilizing element and to limit the motion of the forks 18. Thus the entire attachment may be readily mounted or dismounted on the bed It) when desired. The fork 18 may be readily interchanged with forks of longer or shorter length by merely disconnecting the cable 26 and rods 1h, since there is no other mechanical connection between the bed It), and the attachment. The bracket 11 merely provides a sliding surface upon which the fork structure 16 is operated.

In actual practice this structure has been mounted on light trucks and has been used to carry bins weighing up to a thousand pounds. The capacity of the device naturally depends upon the strength of the various components, and upon the counter balance available in the vehicle. The cylinder 23 may be of any desired type and may be readily operated by conventional power means mounted on the vehicle (not shown). Such power means and controls or cylinders are well known and it is not believed that the particular controls need be further described here. The cylinder 23 would naturally be a double acting cylinder so as to control upward and downward motion of the forks 18.

Thus I have described a very simple fork lift attachment which may be utilized on any vehicle and which may be operated with a minimum of complications. The fork lift attachment provides adequate tilting of the forks for transporting and assures a horizontal position of the forks for loading purposes. It may be readily repaired and mounted and should forestall any major mechanical difiiculties with such an operation. However, it is understood that many mechanical modifications might be made in this structure wtihout deviating from the basic concepts included above. For this reason, only the following claims are intended to set out the extent of this invention.

Having thus described my invention, 1 claim:

1. A fork lift attachment for a vehicle bed, comprising:

a bracket adapted to be fixed to one end edge of the bed and including a pair of parallel spaced planar outer surfaces extending downwardly and outwardly from the bed at an angle to the vertical;

a pair of interconnected L-shaped forks mounted in slidable engagement with said surfaces;

an upright cylinder fixed to the bracket and extending 5 upwardly therefrom;

a piston rod slidably mounted in said cylinder for movement upwardly therefrom;

means operatively connecting said forks and said piston rod for motion of said forks responsive to movement of said piston rod;

and a pair of rigid longitudinally extensible stabilizer rods pivotally connected to the bed inwardly of said bracket and respectively pivoted to said forks adjacent the upper ends thereof.

2. A fork lift attachment as defined in claim 1 wherein said means operatively connecting said fork and said piston rod comprises:

a pulley fastened to the upper end of said piston rod for rotation about a horizontal axis;

and a cable fixed at one end to said bracket, extending over said pulley in engagement therewith, the remaining end of said cable being fixed to said forks.

3. A fork lift attachment for a vehicle bed, comprising:

a rigid bracket adapted to be fixed to one end edge of the bed and including an overhanging member having an outer planar surface directed downwardly and outwardly from the bed surface at an inclined angle relative to the vertical;

a rigid L-shaped fork structure slidably mounted on said bracket in engagement with said outer surface;

power means fixed to said bracket and flexibly connected to said fork structure adapted to vertically position said fork structure relative to said bracket;

and longitudinally extensible stabilizer rod means pivotally connected to said bed inwardly of said bracket and to said fork structure and adapted to angularly position said fork structure relative to said bracket.

4. A fork lift attachment as defined in claim 3 wherein said power means comprises:

an upright cylinder having its base fixed to said bracket and including a vertically movable piston rod extending upwardly therefrom;

a pulley rotatably mounted on said piston rod for rotation about a horizontal axis;

and a flexible member having one end fixed to said fork structure and the remaining end thereof fixed to said bracket, the intermediate portion of said member being entrained over said pulley.

References Cited in the file of this patent UNITED STATES PATENTS 817,790 Marshall Apr. 17, 1906 2,456,434 Manthig Dec. 14, 1948 2,532,717 Hawkins Dec. 5, 1950 2,707,063 Gran et al. Apr. 26, 1955 2,788,199 Ankersheil Apr. 9, 1957 2,867,341 Tieslau Jan. 6, 1959 3,054,520 Maloney Sept. 18, 1962 

3. A FORK LIFT ATTACHMENT FOR A VEHICLE BED, COMPRISING: A RIGID BRACKET ADAPTED TO BE FIXED TO ONE END EDGE OF THE BED AND INLCUDING AN OVERHANGING MEMBER HAVING AN OUTER PLANAR SURFACE DIRECTED DOWNWARDLY AND OUTWARDLY FROM THE BED SURFACE AT AN INCLINED ANGLE RELATIVE TO THE VERTICAL; A RIGID L-SHAPED FORK STRUCTURE SLIDABLY MOUNTED ON SAID BRACKET IN ENGAGMENT WITH SAID OUTER SURFACE; POWER MEANS FIXED TO SAID BRACKET AND FLEXIBLY CONNECTED TO SAID FORK STRUCTURE ADAPTED TO VERTICALLY POSITION SAID FORK STRUCTURE RELATIVE TO SAID BRACKET; AND LONGITUDINALLY EXTENSIBLE STABILIZER ROD MEANS PIVOTALLY CONNECTED TO SAID BED INWARDLY OF SAID BRACKET AND TO SAID FORK STRUCTURE AND ADAPTED TO ANGULARLY POSITION SAID FORK STRUCTURE RELATIVE TO SAID BRACKET. 